Genus: - University of Babylon



Actinomyces

Dr.younis A. AL-khafaji

Actinomyces from Greek "actino" that means mukas and fungus, is a genus of the actinobacteria class of bacteria. They are all Gram-positive and are characterized by contiguous spread, suppurative and granulomatous inflammation, and formation of multiple abscesses and sinus tracts that may discharge sulfur granules." They can be either anaerobic or facultatively anaerobic . Actinomyces species do not form endospores, and, while individual bacteria are rod-shaped, morphologically Actinomyces colonies form fungus-like branched networks of hyphae.

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Actinomycosis GROCOTT'S

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Actinomycosis GRAM'S

Actinomyces are known for causing disease in humans, and for the important role they play in soil ecology. They produce a number of enzymes that help degrade organic plant material, lignin and chitin. As such, their presence is important in the formation of compost.

Many Actinomyces species are opportunistic pathogens of humans and other mammals, particularly in the oral cavity. In rare cases, these bacteria can cause actinomycosis, a disease characterized by the formation of abscesses in the mouth, lungs, or the gastrointestinal tract. Actinomycosis is most frequently caused by Actinomyces israelii. Actinomyces israelii can also rarely cause bacterial endocarditis.

Actinomyces, a thermophilic bacteria, is usually the causative agent of farmer's lung, and bagassosis.

Actinomyces israelii is a species of Actinomyces.

ACTINOMYCOSIS 

Actinomycosis is a chronic suppurative and granulomatous disease of the cervico-facial, thoracic or abdominal areas.

The most common cause of actinomycosis is the organism Actinomyces israelii which infects both man and animals. In cattle, the disease is called "lumpy jaw" because of the huge abscess formed in the angle of the jaw. In man, A. israelii is an endogenous organism that can be isolated from the mouths of healthy people. Frequently, the infected patient has a tooth abscess or a tooth extraction and the endogenous organism becomes established in the traumatized tissue and causes a suppurative infection. These abscesses are not confined to the jaw and may also be found in the thoracic area and abdomen. Another form of actinomycosis is thoracic disease, which is often misdiagnosed as a neoplasm, as it forms a mass that extends to the chest wall. It arises from aspiration of organisms from the oropharynx. Symptoms include chest pain, fever, and weight loss. Abdominal disease is another manifestation of actinomycosis. This can lead to a sinus tract that drains to the abdominal wall or the perianal area. Symptoms include fever, abdominal pain, and weight loss.

Pelvic actinomycosis is a rare but proven complication of intrauterine device. In extreme cases pelvic abscess might develop. The patient usually presents with a pus-draining lesion, so the pus will be the clinical material sent to the laboratory. This diagnosis can be made on the hospital floor. When the vial of pus is rotated, the yellow sulfur granules, characteristic of this organism, can be seen with the naked eye. These granules can also be seen by running sterile water over the gauze used to cover the lesion. The water washes away the purulent material leaving the golden granules on the gauze. This organism, which occurs worldwide, can be seen histologically as "sulfur granules" ( see figures) surrounded by polymorphonuclear cells (PMN) forming the purulent tissue reaction. The organism is a gram positive rod that frequently branches. The laboratory must specifically be instructed to culture for this anaerobic organism. These lesions must be surgically drained prior to antibiotic therapy .

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Sulphur granules in actinomycosis

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Treatment

Treatment for actinomycosis consists of antibiotics such as penicillin or amoxicillin for six to twelve months, as well as surgery if the disease is extensive. Treatment of pelvic actinomycosis associated with intrauterine device involves removal of device and antibiotic treatment .

Diagnosis

Consider actinomycosis when the patient has chronic progression of disease across tissue planes that is mass-like at times, sinus tract development that may heal and recur, and refractory infection after a typical course of antibiotics

NOCARDIOSIS

Nocardiosis primarily presents as a pulmonary disease or brain abscess in the U.S. In Latin America, it is more frequently seen as the cause of a subcutaneous infection, with or without draining abscesses. It can even present as a lesion in the chest wall that drains onto the surface of the body similar to actinomycosis. Brain abscesses are frequent secondary lesions.

The most common species of Nocardia that cause disease in human beings are N. brasiliensis and N. asteroides. These are soil organisms which can also be found endogenously in the sputum of apparently healthy people. N. asteroides (figure 4A) is usually the etiologic agent of pulmonary nocardiosis (figure 5) while N. brasiliensis (figure 4B) is frequently the cause of sub-cutaneous lesions. The material sent to the lab, depending on the presentation of the disease, is sputum, pus, or biopsy material. These organisms rarely form granules. The Nocardia are aerobic, gram-positive rods and stain partially acid-fast (i.e., the acid-fast staining is not uniform) (figure 4B). There are no serological tests, and the drug of choice is Bactrim (Trimethoprim plus sulfamethoxazole). The Nocardia grow readily on most bacteriologic and TB media. The geographic distribution of these organisms is worldwide.

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Figure

Gram-positive acid-fast Nocardia brasiliensis bacteria using a modified Fite-Faraco stain. 80% of cases of Nocardiosis show clinical features of invasive pulmonary infection, disseminated disease, or brain abscess; 20% show cellulitis. In the United States an estimated 500 - 1,000 new cases of Nocardiosis infection occur annually.

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Pleurisy due to nocardiosis 

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Figure . Gram-positive aerobic Nocardia asteroides slide culture reveals chains of amongst aerial mycelia.

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